Abstract Overactive bladder is a chronic and devastating condition in the aging population. Approximately 33 million people in the United States suffer from overactive bladder (OAB) and associated urge incontinence (UI), a chronic medical condition that drastically impairs quality of life and results in an annual economic burden of $66 billion. The psychological aspects of this chronic voiding dysfunction are particularly devastating; patients have increased incidences of depression, social isolation and sleep deprivation. Given that the incidence of UI increases with advancing age, the prevalence of the condition and the total economic burden will continue to rise as the baby boomer population ages. Despite the high social and economic burden, a convenient, safe and effective treatment has yet to be realized. Recently, a minimally invasive neuromodulation device that provides percutaneous posterior tibial nerve stimulation (PTNS) of the afferent sacral nerve, Congentix?s Urgent PC, has shown clinical success; however, this device requires weekly in-clinic treatments as well as repeated placement of an electrode into the posterior tibial nerve, both of which are cost prohibitive and challenging for patient adherence. To address the need for a safe, effective, comfortable, and easy-to-use treatment for OAB, TheraNova has developed TranStimTM, an inexpensive, convenient device that enables a non-invasive, transcutaneous PTNS for treatment of OAB. We have designed TranStim with the following key innovations: 1) Proprietary electrical pulse sequence provides comfortable and supramaximal nerve stimulation without inducing tetany, 2) Delivery of transcutaneous electrical stimulation through the plantar surface of the foot eliminates local pain and skin irritation induced by applied current, 3) Proper afferent nerve stimulation is monitored in real-time, and 4) Easy-to-use device that enables in-home use with patient-tailored therapy. Previously, we have found that transcutaneous PTNS supplied by our TranStim prototype can achieve superior nerve stimulation compared to the commercially available percutaneous PTNS device, Urgent PC, in adult subjects. The goals of this Phase I proposal are to identify a design that will maximize patient compliance and assess its efficacy in a pilot clinical study. First, we will evaluate three different TranStim electrode designs to maximize patient usability while providing tetany-free, supramaximal stimulation of the posterior tibial nerve in 20 elderly subjects (Specific Aim 1). Second, we will determine TranStim?s effectiveness at mitigating urinary UI in 11 elderly patients over an 8- week treatment protocol (Specific Aim 2). The proof-of-principle data obtained through this proposal will demonstrate the therapeutic effect of non-invasive PTNS treatment of UI. This data will also be used to support a Phase II submission, which will include a pivotal, randomized, sham-controlled clinical study to rigorously demonstrate that TranStim is a safe and effective treatment for UI.